Abstract:

Sample pretreatment is the core stage of instrumental analysis. It serves to concentrate trace components， eliminate matrix interference， enhance detection sensitivity， and protect analytical instruments. It is a key step in the analysis and detection of complex environmental samples. Modern sample pretreatment techniques， such as solid-phase （micro）extraction， have the advantages of rapidity， automation， and no or minimal solvent usage， significantly improving the analysis efficiency. The core of solid-phase （micro）extraction technology is the adsorbent material， whose performance directly affects the accuracy of the analysis results. Metal-organic frameworks （MOFs） exhibit significant advantages in the field of adsorption and separation due to their exceptionally high specific surface area， tunable pore structures， nanoscale pore environments， and excellent physicochemical stability. Furthermore， building on MOFs as a foundational platform， researchers have developed different strategies for the controlled incorporation of functional components and the precise design of composite architectures. These strategies have enabled the development of MOFs and their composites. These materials allow for targeted enhancement and control over adsorption capacity， mass transfer efficiency， selectivity， stability， and unique interfacial behaviors. As a result， MOFs and their composites are well-suited to address the multifaceted challenges encountered in complex sample preparation. This review summarizes recent advances in the application of MOFs and their composites within solid-phase （micro）extraction techniques. These techniques include solid-phase extraction （SPE）， dispersive solid-phase extraction （DSPE）， magnetic solid-phase extraction （MSPE）， membrane extraction （ME）， pipette-tip solid-phase extraction （PT-SPE）， membrane-protected solid-phase extraction （MP-SPE）， fiber solid-phase microextraction （Fiber-SPME）， and in-tube solid-phase microextraction （IT-SPME）. From the dual perspectives of adsorbent material applications and methodological development， the review highlights the advantages of MOF-based composites with varied compositions and structures across different sample preparation approaches. It further summarizes the methodological strengths and specific limitations associated with each pretreatment technique. With the expanding application scope of the techniques-particularly in environmental， food， and biomedical fields， increasing demands are being placed on the green synthesis， biocompatibility， and safety of MOFs and their composites. This trend is driving the development of MOFs and related composites toward integrated functionality， environmentally friendly preparation， and application-specific adaptability. From current trends， the design philosophy of transforming powdered materials into monolithic structures represents a significant direction in the development of sample preparation technologies. Both directly and indirectly prepared monolithic materials， as well as those integrated into monolithic devices， retain the performance advantages of powdered adsorbents while offering improved recoverability， portability， and operational convenience. Building on this foundation， techniques such as fiber-SPME and IT-SPME are further advancing toward miniaturization， downsizing， high-throughput operation， and automation. This progress aims to enhance the efficiency of sample preparation and analytical detection. Finally， the future development directions of various currently developed solid-phase （micro）extraction techniques are discussed. The aim is to advance sample preparation technology toward online， high-throughput， and automated systems through comprehensive innovation in adsorbent materials and technical methodologies. Such progress is expected to accelerate the practical application of these techniques in fields such as environmental monitoring， biomedical analysis， and on-site rapid testing. In conclusion， this evolution will ultimately facilitate the transition from laboratory methods to reliable analytical tools.

Key words: metal-organic frameworks （MOFs）, composite materials, solid-phase （micro）extraction, review